Assembly of block pulleys provided with a load measuring system

ABSTRACT

An assembly of pulleys having a reception groove for a flexible pulley-block strap, comprising cheeks, cross-pieces connecting said cheeks, one at least of said pulleys being rotatably mounted between said cheeks on an axis fixed relative to said cheeks, one at least of said pulleys being rotatably mounted between said cheeks and movable in its own plane under the action of the force exerted by the flexible strap on said movable pulley, an elastic system acting on said movable pulley in opposition to said force exerted by the flexible strap on said movable pulley, and a mobile control element carried by one of said cheeks and operatively connected to said movable pulley.

United States Patent Haulotte [54] ASSEMBLY OF BLOCK PULLEYS PROVIDED WITH A LOAD MEASURING SYSTEM [72] Inventor: Georges Haulotte, Rue de la Chambotte, (73), Barberaz, France [22] Filed: May 13,1971

[21] Appl.No.: 142,986

[58] Field of Search 1 77/147, 208-211; 73/141 A [56] References Cited UNlTED STATES PATENTS 7 p 1,236,532 8/1917 Beardetal ..177/147x 14 1 July25, 1972 Primary ExaminerRobert S. Ward, Jr. Attorney-Toren and McGeady 57 ABSTRACT An assembly of pulleys having a reception groove for a flexible pulley-block strap, comprising cheeks, cross-pieces connecting said cheeks, one at least of said pulleys being rotatably mounted between said cheeks on an axis fixed relative to said cheeks, one at least of said pulleys being rotatably mounted between said cheeks and movable in its own plane under the action of the force exerted by the flexible strap on said movable pulley, an elastic system acting on said movable pulley in opposition to said force exerted by the flexible strap on said movable pulley, and a mobile control element carried by one of said cheeks and operatively connected to said movable pulley.

7 5 Drawing Figures Patented July 25, 1972 4 Sheets-Sheet l INVENTOR GEORGEs lffiuLo'rrs Patented July 25, 1972 4 Sheets-Sheet 5 INVENTUR GEORGES HHULOTTE R n W nrrmzmzys,

Patented July 25, 1972 4 Sheets-Sheet 4 INVENTM G Eoflcss HRULOTTE ASSEMBLY OF BLOCK PULLEYS PROVIDED WITH A LOAD MEASURING SYSTEM The invention relates to the assemblies which are made up of several pulleys, having a reception groove for a flexible pulley-block strap, mounted for rotation between cheeks connected by cross-pieces and which are provided with a system for measuring the load supported by these pulleys.

Such assemblies of pulleys are encountered in hoisting appliances, handling appliances or similar appliances. These assemblies can be effected in the form of movable blocks, or else be incorporated into the appliance itself, as is the case, for example, for the assemblies of pulleys mounted on the jib head of a crane.

In the known assemblies of this type, all the pulleys can be shifted, as a whole, with respect to the checks, in opposition to elastic restoring means and they are connected to a load-indicating member mounted on an external check. The result is that the accuracy of the indication of the value of the load to which the assembly is subjected varies according to the number of pulleys effectively used in each case of blocking in question.

The aim of the invention is to provide an assembly of block pulleys which does not have the aforesaid disadvantage of conventional assemblies.

To this end, in the assembly of block pulleys according to the invention, one, at least, of the pulleys is carried by a part fixed in relation to the cheeks, while one, at least, of the pulleys is movable in its plane in relation to the cheeks under the action of the force exerted, by the flexible strap, on the said movable pulley, in opposition to an elastic system, the said movable pulley being linked to a movable control element carried by the one of the said cheeks and the position of which is determined by that ofthe movable pulley.

By virtue of this special arrangement, the same sensitivity of measurement of the load can be preserved for different numbers of block strands. Thus, for example, with a block comprising one fixed pulley and one movable pulley, for a predetermined load two strands on the movable pulley alone can be used and, for a double load, four strands can be used, namely two strands on the movable pulley and two strands on the fixed pulley, while preserving the same sensitivity of measurement, since the movable pulley is always subjected only to the same load in the two cases. In a block having three pulleys there could be one fixed pulley and two movable pulleys connected, respectively, to two load indicators arranged on the two external cheeks of the block, respectively. One could thus provide a pulley block having two, four or six strands with the same sensitivity of measurement on the two indicators. In a more general manner, it can be said that one can provide assemblies of almost unlimited capacity with an acceptable accuracy of measurement, seeing that the evaluation of the total load is effected by means of a measurement carried out by only one of the pulleys. Thus, for example, the measurement of a load of 100 tons on a block having eight sheaves will be effected by the displacement of a pulley supporting only 12.5 tons.

According to another feature of the invention, the movable pulley is in the shape of a grooved rim mounted for rotation on a recessed support part movable with regard to the cheeks, the elastic system being arranged inside the said recessed support part and interposed between the inner edge of this part and a cross-piece part connecting the cheeks through the recessed part. By virtue of this arrangement, assemblies of pulleys with load indicators on two opposed checks can be provided, under a very reduced radial space occupied, since the connections of the pulleys to the indicators are effected through the recessed support parts.

The invention will be better understood by reading the following description and by examining the attached drawings which show, by way of non-restrictive example, one embodiment of an assembly of block pulleys in accordance with the invention.

In these drawings FIG. I is a front view of the assembly FIG. 2 is a section taken along the line lIlI of FIG. I

FIG. 3 is a section taken along the line III-III of FIG. 2

FIG. 4 is, on a larger scale, a section taken along the line IVIV of FIG. 3; and

FIG. 5 shows the dial of the indicator device situated on the cheek opposite that visible in FIG. I.

The block represented in FIG. I and 2 comprises three pulleys, namely one central pulley l and two lateral pulleys 2, 3 mounted in the gaps between two outer cheeks 5, 6 and two inner cheeks 7, 8, connected one to another by stay-bolts II. The upper part of the block is provided with a part 13 connected to the two upper stay-bolts and having an eye 14. A suspension hook 17, for example of the gudgeon type, is mounted in the lower part of the outer cheeks 5, 6, preferably in a removable manner, by means of an pin 17 provided with a handle 18. Handles 19 facilitate the manipulations of the block.

The three pulleys l, 2, 3 are constituted by simple grooved rims mounted for rotation, through the medium of rolling bodies, such as 24, on recessed parts 25, 26, 27 respectively, (see also FIG. 3), nevertheless one of these three parts, namely the support part 27 of the lateral pulley 3, is fixed rigidly in relation to the cheeks of the block, while the other two support parts 25, 26 are movable in relation to these latter.

The recessed support part 27 is pressed, by means of screws 33, between stay-bolts 31, 32 integral respectively with the cheeks 8 and 6.

The support part 25 is mounted pivotally, for example through the medium of ball bearings or needle bearings 35, on a shaft 37 fixed, by its two ends, by means of nuts 38, 39 in two corresponding holes of the outer cheek 5 and of the inner cheek 8, the said shaft traversing freely a corresponding hole of the other inner cheek 7. The axis of the shaft 37 (see also FIG. 3) is off-set with regard to the geometric axis 41 of the assembly of the pulleys, laterally with regard to the general direction of the flexible stands 43 which pass over the pulleys.

Under the effect of the pull of the flexible strands 43, the support part 25 can turn with regard to the checks of the block about the shaft 37, in the direction of the arrow f, in opposition to the force of an elastic restoring system constituted by a stacking of Belleville or Schnorr washers 44 (see also FIG. 4) bearing, at one of its ends, against a recess 45 in the shape of cylindrical surface portion contrived in the inner edge of the hollowed-out support part 25, through the medium of a flange 49 ofa shaft 46, an adjusting threaded rod 47 and a plug 48 in a corresponding cylinder portion, and, by its other end, on the inner cheeks 7 and 8, through the medium of an annular thrust part 52 and of a pin 53 whose two ends are engaged in two corresponding holes 54, 55 of the two cheeks 7 and 8. The upper end of the shaft 46 is in the shape of a fork 57 which grips round the pin 53 so as to ensure a good guidance of the stack of elastic washers 44.

The support part 25 carries a toothed sector 61 coaxial with the shaft 37 and in mesh with a toothed pinion 62 secured to one end of a shaft 63 which pivots in two bearings 64, 65 fixed, respectively, in the two ends of a sleeve 67 traversing the inner cheek 8 and the outer cheek 6 to which it is secured. The other end of the shaft 63 carries a needle 68 movable in front of a scale 69 (FIG. 1) indicating loads in tons, for example, from 0 to 5 in this example. The scale 69 is situated on a dial 72 formed by a part which is stamped in a cover 73 and which is concentric with the shaft 63 of the needle 68.

The mounting of the lateral pulley 2 is identical with that of the central pulley I. The support part 26 of this outer pulley is connected to another indicating needle 68A which shifts in front of a dial 72A carried by a hood 73A fixed on the other outer cheek 5 of the block. The elements of the transmission between the support part 26 and the needle 68A are similar to those which connect the support part 25 to the needle 68 and they have been designated by the same reference numbers as signed the indication A.

The dial 72A carries two scales 75, 76 which, in this example, extend respectively from O to 10 and from O to 15 tons.

The operation of the block is as follows:

When the block is used with only two single strands, that is to say solely the central pulley l, the load can be read on the dial 72 (FIG. 1) the graduations of which extend from to tons maximum.

When the block is used with four single strands, that is to say with the two lateral pulleys 2 and 3, the loads are read on the scale 75 of the dial 72A (H6. 5) the values of which extend from 0 to tons, while if a pulley block having six single strands is used, that is to say the whole of the three pulleys, the value of the load is read from the scale 76 of the dial 72A the values of which extend from 0 to tons. Whichever may be, of these three conditions, of use, the one which is adopted, each of the single strands of the flexible strap 43 is subjected to a uniform maximum force of 2.5 tons and the opposing spring constituted by the stackings of Belleville washers, such as 44, always work in the same conditions, between the zero load and the maximum load, so that the sensitivity is the same, whatever the number of pulleys used for the pulley block.

The needle indicating device could be replaced by any other suitable indicating device and, for example, by a system of electrical contacts which would be actuated in response to the angular displacement of the pivoting support parts 25 and 26, in terms of the loads supported by the block. Such an arrangement would be very advantageous also, for example, for assemblies of pulleys mounted on the jib head of a crane.

There could also be added, in every case, an alarm system controlled by a safety contact actuated at the end of travel of the movement of the support parts with regard to the cheeks.

Of course, the invention is not limited to the embodiment described and shown; modifications can be made thereto, in accordance with the applications envisaged, without departing, for all that, from the framework of the invention.

What is claimed is:

1. An assembly of pulleys having a reception groove for a flexible pulley-block strap, comprising cheeks, cross-pieces connecting said cheeks, one at least of said pulleys being rotatably mounted between said cheeks on an axis fixed relative to said cheeks, one at least of said pulleys being rotatably mounted between said cheeks and movable in its own plane under the action of the force exerted by the flexible strap on said movable pulley, an elastic system acting on said movable pulley in opposition to said force exerted by the flexible strap on said movable pulley, and a mobile control element carried by one of said cheeks and operatively connected to said movable pulley.

2. An assembly of pulleys according to claim 1, with an annular support part having an inner edge and movable between said checks in the direction of movement of said movable pulley, said movable pulley being in a shape of a grooved rim mounted for rotation of said annular support part, said assembly further comprisinG an additional cross-piece connecting said cheeks throughout said annular support part, said elastic system being arranged inside said annular support part between the inner edge of said part and said additional crosspiece.

3. An assembly of pulleys according to claim 2, further comprising a shaft carried by said cheeks, said annular support part being mounted for rotation on said shaft, said shaft being off-set in relation to the axis of said pulley, laterally in relation to the general direction of said flexible strap.

4. An assembly of pulleys according to claim 2, wherein said mobile control element is operatively connected to said annular support part.

5. An assembly of pulleYs according to claim 3, wherein said mobile control element is operatively connected to said annular support part, said mobile control element being constituted by a pivoting needle, said assembly further comprising a toothed pinion secured to said needle, a toothed sector secured to said annular support part and the axis of which is situated on the pivoting axis of said annular support part, said toothed sector being in mesh with said toothed pinion.

6. An assembly pulleys according to claim 1, characterized in that it comprises two movable pulleys connected, respectively, to two mobile control elements carried, respectively, by

the outer cheeks of the assembly.

7. An assembly of pulleys according to claim 1, wherein said control element is constituted by an electrical contact. 

1. An assembly of pulleys having a reception groove for a flexible pulley-block strap, comprising cheeks, cross-pieces connecting said cheeks, one at least of said pulleys being rotatably mounted between said cheeks on an axis fixed relative to said cheeks, one at least of said pulleys being rotaTably mounted between said cheeks and movable in its own plane under the action of the force exerted by the flexible strap on said movable pulley, an elastic system acting on said movable pulley in opposition to said force exerted by the flexible strap on said movable pulley, and a mobile control element carried by one of said cheeks and operatively connected to said movable pulley.
 2. An assembly of pulleys according to claim 1, with an annular support part having an inner edge and movable between said cheeks in the direction of movement of said movable pulley, said movable pulley being in a shape of a grooved rim mounted for rotation of said annular support part, said assembly further comprisinG an additional cross-piece connecting said cheeks throughout said annular support part, said elastic system being arranged inside said annular support part between the inner edge of said part and said additional cross-piece.
 3. An assembly of pulleys according to claim 2, further comprising a shaft carried by said cheeks, said annular support part being mounted for rotation on said shaft, said shaft being off-set in relation to the axis of said pulley, laterally in relation to the general direction of said flexible strap.
 4. An assembly of pulleys according to claim 2, wherein said mobile control element is operatively connected to said annular support part.
 5. An assembly of pulleYs according to claim 3, wherein said mobile control element is operatively connected to said annular support part, said mobile control element being constituted by a pivoting needle, said assembly further comprising a toothed pinion secured to said needle, a toothed sector secured to said annular support part and the axis of which is situated on the pivoting axis of said annular support part, said toothed sector being in mesh with said toothed pinion.
 6. An assembly pulleys according to claim 1, characterized in that it comprises two movable pulleys connected, respectively, to two mobile control elements carried, respectively, by the outer cheeks of the assembly.
 7. An assembly of pulleys according to claim 1, wherein said control element is constituted by an electrical contact. 